This invention relates to an improved flow control valve, which provides a substantially in-line flow direction, and which, in its preferred embodiment, can be inserted within a continuous length of pipe. The valve itself is hermetically sealed and is controllable for variable flow positioning without requiring any shafts or any moving elements to be inserted through the valve wall. All valve seals are therefore stratic pressure seals, and the valve is hermetically sealed, being immersed completely in the fluid but having no chance of leakage or cross contamination from outside influences.
The valve comprises an improved rolling diaphragm mechanism especially modified to provide an even-fluid balance and installed so that the flow of liquid through the valve aide the sealing action of the diaphragm. The mechanical configuration is such that, in the closed position, pressure differential forces across the diaphragm resisting opening are completely balanced, thus enhancing the minimum opening forces characteristic of a rolling diaphragm valve mechanism, and permitting higher fluid pressure differentials to be valued that has heretofore been possible with such valving mechandisms.
The valve is driven by a novel magnetically driven screw mechanism.
The magnetic drive for the screw comprises a multi-pole radial driven element with a matching external multi-pole magnetic drive. This drive mechanism provides considerably stronger magnetic drive forces than the linear magnetic positioning devices currently used in the art, and in addition, provides for increased positional control by permitting arbitrarily small angular positioning of the valve internal drive mechanism.
In summary, the valve represents an improved in-line flow control mechanism providing significantly increased actuating force against pressure differential and flow, a significantly increased flow control capability, and a total hermetical seal against outside contamination, all embodied in an in-line mechanism which can be inserted within an existing length of flow pipe.